1. Field of the Invention
The present invention relates to a method and apparatus for transmitting and receiving resource allocation scheme information in a wireless communication system.
2. Description of the Related Art
Wireless communication systems may be classified according to various criterions. Depending on how total system resources are controlled, wireless communication systems may be divided into distributed communication systems and centralized communication systems. A Wireless Local Area Network (WLAN) is an example of a distributed system, and a legacy system, such as a cellular network, is an example of a centralized system.
In a centralized communication system, a Base Station (BS) or an Advanced BS (ABS) manages all resources. That is, the BS allocates resources to a Mobile Station (MS) or an Advanced MS (AMS) for transmission of uplink data as well as transmission of downlink data. Thus, an MS having been allocated resources for uplink data transmission among MSs within the service area of the BS can transmit its uplink data.
Examples of centralized systems include an Institute of Electrical and Electronics Engineers (IEEE) 802.16m system and an IEEE 802.16e system. The IEEE 802.16m system provides a variety of uplink resource allocation schemes corresponding to the types of uplink data required for various services. The IEEE 802.16e system provides an Unsolicited Grant Service (UGS), a real-time Polling Service (rtPS), an extended rtPS (ertPS), a non-real-time Polling Service (nrtPS), and a Best Effort (BE) service. In addition to the service types, the IEEE 802.16m system can provide an adaptive Grant Polling (aGP) service.
The aGP service is a data service type to which a plurality of Quality of Service (QoS) parameter sets representing resource allocation schemes are applicable. For example, if an MS conducts communication using a Voice over Internet Protocol (VoIP) service, the VoIP service may have different resource allocation periods and different amounts of resources required during a talk spurt as compared to a silence spurt according to an audio CODEC used by the VoIP service. In a case of an Adaptive Multi-Rate (AMR) audio CODEC, about 40 bytes are required every 20 ms for a talk spurt and about 10 bytes are required every 160 ms for a silence spurt. When the MS transmits uplink data using such an AMR audio CODEC, allocating two QoS parameter sets to the MS may reduce unnecessary resource allocation in the wireless communication system.
Specifically, the aGP service defines, for example, a primary QoS parameter set specifying a resource amount and a resource allocation period for a talk spurt and a secondary QoS parameter set specifying a resource amount and a resource allocation period for a silence spurt. Thus, the two resource allocation schemes (i.e., the two QoS parameter sets) are used separately and respectively for the talk spurt and the silence spurt.
Each time a new connection is added for communication between a BS and an MS, the BS and the MS determine an uplink resource allocation scheme for the new connection. For this purpose, they negotiate by exchanging Dynamic Service Addition (DSA) messages. When the BS and the MS agree to use the aGP service, the DSA messages define a primary QoS parameter set and a secondary QoS parameter set.
In the method discussed above, a process to change the QoS parameter sets is to be determined for resource allocation. The IEEE 802.16m system considers two processes for changing QoS parameter sets, that is, MS-initiated adaptation and BS-initiated adaptation.
However, no specific method has been defined in relation to changing a resource allocation scheme in the IEEE 802.16m system. Accordingly, there exists a need for defining a specific resource allocation method in a wireless communication system.